Each year in the United States, some six million people present to emergency departments with chest pain. Although only 15% to 20% of these patients are ultimately diagnosed with an acute coronary syndrome (ACS), about half are admitted for evaluation. Conversely, 2% of patients with ACS are mistakenly discharged. As patients with ACS have a relatively high risk of major adverse cardiovascular events in the short term, there is a clear need for accurate objective tools by which to identify them.
Currently used markers for cardiac damage suffer disadvantages that limit their clinical usefulness. Cardiac enzyme assays have formed the basis for determining whether or not there is damage to the cardiac muscle. Unfortunately, the standard creatine kinase-MB (CK-MB) assay is not reliable in excluding infarction until 10 to 12 hours after the onset of chest pain. Earlier diagnosis would have very specific advantages with regard to fibrinolytic therapy and triage. In additional, more sensitive markers of cardiac toxicity would allow earlier detection of adverse effects of, e.g., drug therapy.